EPA Noise notice

[brc]

So! 2.5" exhuast is no good apparently. EPA want me to do a noise test on the sri-t. What do i do ? :( What are my options to pass the test.

[sooty]

A) borrow someone else's exhaust for the day
B) get yours modified with a baffle plate in one of the joins and remove it after
C) if you want to pass and keep your exhaust legal, get another/better resonator

[Jerram]

put the old I(stock) exhaust back on for the test, then install a "hotdog" to the exhaust to quieten it when you put it back on.

[gman]

It's not the diameter it's the mufflers.

You can get a 3" past EPA noise with the right noise suppression.

Two options:

1) fit another muffler or replace one you have with a larger/better/less straight through one

2) fit a sound baffle in one of the flange joins (which is literally a metal sheet with holes in it). This will drop sound a lot and is then removable after testing.

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[brc]

got ya. what is the legal db for sri-t?

[brc]

It's not the diameter it's the mufflers.

You can get a 3" past EPA noise with the right noise suppression.

Two options:

1) fit another muffler or replace one you have with a larger/better/less straight through one

2) fit a sound baffle in one of the flange joins (which is literally a metal sheet with holes in it). This will drop sound a lot and is then removable after testing.

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sorry for double post, vwhat is best option to keep as is and what is general cost involved?

[guy 27]

got ya. what is the legal db for sri-t?

i'm sure theres another thread on here that says it all. iirc its 95db.

[gman]

Use a baffle plate and you can make 1 for $20 with a plate, a drill and a 6-10mm drill bit.

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[guy 27]

boosted_astra has a spare stock exhaust system. send him a pm and see if he will sell or lend it out.

[brc]

If I get a better muffler etc, will this effect my bhp? What I'm after is a solution that:

1. Meets EPA standards
2. Keeps, or at least comes close to the exhuast I have.

Will a baffle plate effect the speed of my car? or just silence it a bit?

[hazrd]

95dB is the legal limit :)

[DIXIE]

careful though.. the limit doesnt apply to peak revs, it applies to overall, and you will gain about 4dbA on back off (happened to me)
also, the limit is 90dbA not 95.

best bet is put your standard system back on, and you wont have any dramas. my 2.5" system was 87dbA at peak revs, and 94dbA on backoff (stupid manuals).. so yeah, get a stock system and u wont have a problem.. get ur certificate, mail it off, chuck ur good system back on and away u go :D

[Wraith]

Re: above, last I heard from someone here in Melb. that copped an EPA slip, the db noise range was measured with the engine holding at 3000rpm not across a wide spread...not sure if that's the case across the board ??

And yeah as suggested above, put the stock exhaust or at least mufflers if they fit back on certainly does not have anything to do with pipe dia.

[DIXIE]

@wraith - i copped one of these noise notices last month.. and the measurement is across the whole board, not at 3000rpm (i know, because i failed because of it lol)

[Wraith]

@wraith - i copped one of these noise notices last month.. and the measurement is across the whole board, not at 3000rpm (i know, because i failed because of it lol)

That's fair enough, it may have changed the guy I know who copped the same was from a few years ago, and as far as I can remember the place he had to attend for the test was somewhere in Altona ??

Suffice to say, he too failed 1st time around LOL...he ended up changing his mufflers whereas the 1st time, what he did to muffle it down was shove steel wool bundles in the pipes just before the mufflers...

[DIXIE]

LOL full habibspec.. depends what kind of notice you get.. if you get a full epa inspection notice (emissions and all), then you have to go to the actual EPA testing place which is in heidelberg or watsonia or something (where I've had to take the VL).. but the noise ones are much simpler..
basically if a cop hears you, and thinks your exhaust is too loud, they'll just punch your plates in the system and you'll get a letter for noise testing (N)..
then you can take it to any epa approved tester (at an exhaust shop) (they give you a list of places), and you go there, and then they **** you around lol

[AfterBurner]

When i had my bike tested last year for rego, it was at a specific rev (plate states 94dB@6500rpm)...

Whatever is written on the compliance plate has to be the reference used for testing... This may not necessarily be the peak as that depends on ur resonator fitted.

As for the dB readings... There is a difference between dBA & deciBels in general...

Quote: source - http://www.animations.physics.unsw.edu.au/jw/dB.htm

"The filters used for dBA and dBC

The most widely used sound level filter is the A scale, which roughly corresponds to the inverse of the 40 dB (at 1 kHz) equal-loudness curve. Using this filter, the sound level meter is thus less sensitive to very high and very low frequencies. Measurements made on this scale are expressed as dBA. The C scale is practically linear over several octaves and is thus suitable for subjective measurements only for very high sound levels. Measurements made on this scale are expressed as dBC. There is also a (rarely used) B weighting scale, intermediate between A and C. The figure below shows the response of the A filter (left) and C filter, with gains in dB given with respect to 1 kHz."

[coyotte]

mmmm.... Just been done last week by a group of cops standing out the front of Moonee Ponds police station drinking coffee & having a smoke when I drove past (slowely). Based on all of the above, a 3" cat back system thats been on 5 years is going to FAIL. Shame I didn't keep the stock exhaust in the garage : ( another revenue raiser !

[dutchy]

Just weld a hotdog in the middle, makes a big difference in noise but does not lower performance. You can get these for 75 dollars or so.

[coyotte]

Well had the EPA reading done. Reading was 95dB. @ 4200RPM.
However, on over run it peaked at 105dB ! (15dB. OVER the limit)
Its ashame, as the 3" had been on for 5yrs, and had a great burble.
So, its going back to basics prior to trade in, (or sell privately).
Looking at a new '11 black Renault Megane RS Cup.